Inertial Reference Unit Fault Detection via MSPRT

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Solution Overview

Problem

Existing aircraft flight control systems face challenges in detecting generic failures in Inertial Reference Units (IRUs) and other control system components, which can lead to unsafe operation if not detected, as traditional methods rely on hardware redundancy and comparison of outputs, failing to identify simultaneous generic errors.

Innovation Solution

A fly-by-wire flight control system that receives signals from multiple Inertial Reference Systems and Augmented Direct Mode Sensors, performs signal selection and fault detection, and provides vehicle control command signals based on the determination of fault conditions, using techniques like Modified Sequential Probability Ratio Test (MSPRT) to detect both random and generic failures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If hardware redundancy and output comparison methods are used for fault detection, then system reliability is improved, but the ability to detect generic failures is insufficient

Engineering Contradiction:
Improvefault detection capabilityVSAvoidfailure detection accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent replaces traditional hardware redundancy comparison methods with a signal processing-based fault detection system. The MSPRT algorithm processes sensor signals to detect both random and generic failures, substituting mechanical/hardware comparison approaches with computational signal analysis that can identify subtle failure patterns invisible to traditional methods.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the detection parameter from simple output value comparison to statistical signal characteristics analysis. By monitoring signal parameters through MSPRT (Modified Sequential Probability Ratio Test), the system detects failures based on statistical deviations in signal behavior rather than direct hardware output comparison, enabling detection of generic failures affecting multiple sensors simultaneously.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If traditional fault detection methods are used, then system complexity is reduced, but safety cannot be ensured with failed system elements

Engineering Contradiction:
Improvesafety with failed elementsVSAvoidfault detection system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces an intermediary fault detection layer between the Inertial Reference Units and the flight control system. The MSPRT-based monitor acts as a mediator that processes signals from multiple IRUs and ADMS, performing statistical analysis to detect failures before they compromise safety, thereby enabling continued safe operation with degraded systems without requiring complex reconfiguration.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If multiple Inertial Reference Units are used for redundancy, then measurement reliability is improved, but the ability to detect simultaneous generic errors is lost

Engineering Contradiction:
Improvemeasurement reliabilityVSAvoidgeneric failure detection
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent implements a feedback-based fault detection mechanism where the MSPRT algorithm continuously monitors signals from multiple IRUs and ADMS, comparing expected statistical behavior against actual measurements. When generic failures occur affecting multiple sensors simultaneously, the feedback loop detects the correlated deviations through statistical analysis, maintaining detection capability despite the redundancy that normally masks such failures.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2269003B1Integrity monitoring of internal reference unit
Publication Date: 2018.01.24 BOMBARDIER INC
  • EP2269003B1 patent drawingFigure 1
  • EP2269003B1 patent drawingFigure 2~3
  • EP2269003B1 patent drawingFigure 4

AI summary

Systems 100, methods, and machine-executable programming products adapted for the control of aircraft or other vehicles by receiving from at least one lnertial Reference System (IRS) 102 comprising a plurality of lnertial Reference Units (IRUs) 110 signals representing vehicle state data; receiving from at least one Augmented Direct Mode Sensor (ADMS) 106 signals representing independently-acquired vehicle state data corresponding to least a subset of the signals received from the IRS; performing signal selection and fault detection processes on the signals received from the at least one IRS and on the corresponding signals received from the ADMS; based at least partly on the signal and fault detection processes, determining whether at least one component of at least one of the IRS and ADMS is in a fault condition; and based on the determination whether the at least one component is in a fault condition, providing to at least one vehicle control system device one or more vehicle control command signals.